This invention relates generally to the manufacture of dynamoelectric machines and more particularly to an improved means for retaining balance weights on a cast squirrel cage rotor.
In the production of laminated rotors incorporating cast squirrel cage windings, that is, conductor bars integrally joined at each end of a laminated stack by end rings, there has been a practical difficulty in satisfactorily securing relatively heavy balance weights to the rotor. The balance weights are attached to the end rings to compensate for an unbalance in the mass system with which the rotors are associated; e.g., a single piston hermetically sealed refrigeration compressor with a crankshaft introducing a dynamic unbalance into the system. According to a more general practice in the past, balance weights have been attached to the end rings on aluminum projections that were cast integrally with the end rings. This approach, however, may not be satisfactory when using balance weights of a higher mass because of concern that the weights might tear loose during normal operation. Any approach would, more desirably, be one that was economical and simple to practice on a day-to-day basis.
In view of the foregoing, it should now be understood that it would be desirable to provide a balance weight securing means that would be both uncomplicated and inexpensive and yet would securely retain weights of a heavier mass.
Accordingly, one object of the present invention is to provide a rotor with improved means for retaining a balance weight thereon.